Spring and dispenser comprising such a spring

ABSTRACT

A spring ( 4 ) comprising two branches ( 41, 42 ) is connected by a bend ( 40 ) such that the branches form, in the idle position, an acute angle. Said branches are elastically mobile in relation to each other by relative pivoting around the bend until they come into contact with each other so as to be extended relatively in parallel. The spring also comprises a spring stiffness variation systems ( 43, 44 ) which produce different stiffnesses depending on whether the spring is compressed or slackened. Said variation system producing a low stiffness when the branches are extended relatively in parallel and a greater stiffness when the branches are forced together from the idle position.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit under 35 U.S.C. §119(e) ofpending U.S. provisional patent application Serial No. 60/342,369, filedDec. 27, 2001, and priority under 35 U.S.C. §119(a)-(d) of French patentapplication No. FR-01.14725, filed Nov. 14, 2001.

TECHNICAL FIELD

[0002] The present invention relates to a spring and a dispensing deviceusing such a spring as a return spring used to return the dispenser tothe idle position. However, the spring must not be restricted only touse in such a dispenser. Indeed, it may also be used in any other systemrequiring elastic return means.

BACKGROUND OF THE INVENTION

[0003] Numerous types of springs already exist and the most commonlyused is the conventional cylindrical, and more rarely conical, shapedspiral spring. When such a spiral spring is to be mounted in anautomated manner in a specific device or system, this requires theorientation and seizure of the spring using a suitable machine such as arobot. This is due to the fact that it is difficult for a spiral springto remain upright due to its cylindrical and elongated configuration.Therefore, it cannot be fed directly into a device at a suitable pointfrom bulk storage.

[0004] The present invention defines another type of spring, wherein theorientation is advantageously easier, in that the spring is positionedalmost automatically in a position wherein it can perform its functionas a spring.

[0005] The document U.S. Pat. No. 2,432,288 already discloses a springcomposed of two curved blades against each other, the end of one bladecoming into contact with the other blade. When pressing on this springto bring the blades closer together, it is impossible to bring the twoblades back into contact with each other. Therefore, this spring mustnever by flat, i.e. be very thin.

[0006] The document U.S. Pat. No. 4,932,508 also discloses azigzag-shaped blade spring. Each blade of the spring is formed with awindow in which a curved tab is cut, which may come into contact withthe other blade when the spring is compressed. The free end of the tabslides on the blade when the spring is compressed.

[0007] In these springs according to the prior art, it is not possibleto produce them in an extremely flat configuration, since the meansproducing the stiffness of the spring, in this case, the end of a bladeor the tab, do not permit it.

SUMMARY OF THE INVENTION

[0008] The aim of the present invention is to remedy this drawback ofthe prior art by defining a spring which can easily adopt an extremelyflat configuration, while offering satisfactory stiffness undercompression.

[0009] For this purpose, the present invention relates to a springcomprising two branches connected by a bend such that the branches form,in the idle position, an acute angle, said branches being elasticallymobile in relation to each other by relative pivoting around the benduntil they come into contact with each other so as to be extendedrelatively in parallel, characterised in that it comprises springstiffness variation means which produce different stiffnesses dependingon whether the spring is compressed or slackened, said variation meansproducing a low stiffness when the branches are extended relatively inparallel and a greater stiffness when the branches are forced togetherfrom the idle position. The branches of the spring are relativelyidentical and advantageously straight and relatively plane. In addition,the width of the branches is greater than half of their length. For thisreason, the spring is positioned almost automatically on one of thesetwo branches such that it can fulfil its function as spring by pressingon the other branch which is not resting on the bearing surface.Advantageously, the bend extends over the entire branch width.

[0010] Therefore, the spring comprises a particularly simpleconfiguration in the form of a slightly open hairpin that can easily bemanufactured from a cut and bent metal blade or by moulding plastics.

[0011] The stiffness variation means only become fully operative afteran initial release of the branches when they are initially broughtcloser together again. It is the variation means that act on the springstiffness and not the bend. The variation means act in a way similar toa spring arming function which gives the spring its full stiffness.

[0012] When the variation means are fully operative, the role of thebend is limited to a joint between the two branches, but only representsa low contribution to the total spring stiffness. The elasticdeformation of the spring then takes place on the branches and/orvariation means.

[0013] Advantageously, the spring stiffness variation means compriselocking means preventing the branches from being returned to arelatively parallel position from the idle position.

[0014] According to one embodiment of the invention, the variation meanscomprise at least one tab attached to a so-called first branch andextending between the two branches to the other so-called second branch,said tab comprising one free end and one end connected to the firstbranch, said second branch comprising a stop housing intended to receivethe free end of the tab, said free end being locked at a stop in thehousing when the two branches are forced against each other, thuspreventing the branches from being brought against each other bypivoting around the bend. If the free end of the tab is prevented frombeing inserted in the housing of the second branch when the branches arebrought closer together, it is then possible to flatten the springcompletely with the elastically deformed tab so as to extend relativelyparallel to and between the branches. In this flattened configuration,the tab contributes to the total stiffness of the spring in conjunctionwith the bend. It is the elastic deformation of the tab on itsconnection with the branch that generates the stiffness. On the otherhand, if the tab is left free from any outside strain, then its free endis automatically inserted in the housing of the second branch andremains locked even if the spring is at maximum compression. Thestiffness of the spring is in this case much greater than that of thespring when it is flattened with the tab which extends between theparallel branches.

[0015] According to a practical embodiment, the tab extends with itsfree end oriented relatively towards the bend, the free end of the tabbeing located between the stop housing and the bend when the branchesare relatively parallel. In an alternative embodiment, the tab extendswith its free end oriented relatively towards the free ends of thebranches, the free end of the tab being located between the stop housingand the free ends of the tabs when the branches are relatively parallel.Advantageously, the first branch forms a window wherein the tab ishoused by elastic deformation when the two branches are extendedrelatively in parallel.

[0016] The invention also relates to a fluid product dispensercomprising:

[0017] a reservoir containing said fluid product and equipped with atleast one actuating wall on which pressure is exerted to reduce thevolume of the reservoir,

[0018] a dispensing outlet through which the fluid product is dispensed,

[0019] characterised in that the reservoir contains a spring as definedabove. Advantageously, a removable sealing component seals thedispensing outlet and thus isolates the reservoir from the outside, thespring being compressed so as to occupy a minimum volume when thesealing component seals the dispensing outlet. In this way, the springis slackened to increase the volume of the reservoir when the sealingcomponent is removed by introducing gas into the reservoir via thedispensing outlet.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The use of such a spring is particularly advantageous in such afluid product dispenser, since it is simply necessary to deposit thespring in the reservoir when the dispenser is being manufactured,without having to worry about its specific orientation, given that thespring is automatically positioned on one of the two branches. This doesaway with the need for a prior spring orientation and seizure operation.In addition, such a spring may be manufactured at a low cost.

[0021] The invention will now be described in more detail with referenceto the figures attached, showing a non-restrictive example of anembodiment of the spring according to the invention, and implementationin a specific fluid product dispenser.

[0022] In the figures:

[0023]FIG. 1 is a perspective view of the spring in FIG. 1,

[0024]FIG. 2 is a vertical transverse section view of the spring in FIG.1 in the compressed state,

[0025]FIG. 3 is a view of the spring in FIGS. 1 and 3 during compressionwith fully operative variation means,

[0026]FIG. 4 is a vertical transverse section view of a fluid productdispenser using a spring in FIGS. 1 to 3, said dispenser not being used,and

[0027]FIG. 5 is a section view of the dispenser in FIG. 4 ready for use.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0028] The spring shown in the figures and used to illustrate thepresent invention is presented in the general form of an open pin. Thespring referred to in general with the numerical reference 4 comprisestwo branches 41 and 42 connected together at one of their ends by a bend40. The two branches 41 and 42 are extended in relation to each other,producing an acute angle, for example located between 20 and 60°. It iseasy to understand that such a pin may easily be deformed elastically bybringing the branches closer together, which is performed by adeformation/pivoting movement around the bend 40. By choosing a suitablematerial such as metal or plastic, with good shape retention, the twobranches return elastically to their original position once the pressureforce ceases to be exerted on said branches.

[0029] Preferentially, the branches of the spring are relatively wide inrelation to their length: the width of the branches may for example begreater than half the length of the branches. In addition, the twobranches are advantageously relatively straight and plane, such thatthey offer an extensive and particularly stable bearing surface.Preferentially, the two branches are relatively identical such that itis completely irrelevant whether the spring rests on either of thebranches. With such a configuration, the spring is automaticallypositioned on one of these two branches. It is indeed practicallyimpossible for the spring to be positioned on the edge of the branches:this is rendered even more improbable by the fact that the free end ofthe branches is rounded.

[0030] According to the invention, the spring comprises spring stiffnessvariation means capable of preventing the branches from being broughtrelatively in parallel. The variation means are inoperative or produce alow stiffness when the branches extend relatively in parallel and, onthe other hand, become fully operative or produce a higher stiffnesswhen the branches are forced against each other from the idle position.These variation means are presented in this case in the form of a tab 43which extends from the branch 41 to the other branch 42. In other words,the tab 43 extends between the two branches in the acute angle. The tab43 comprises one connected end of the branch 41 and one free end 431which points towards the other branch 42. The tab 43 also extends in aninclined manner such that the free end 431 is oriented towards the bend40. However, it is possible to envisage an alternative embodiment forthe tab 43 such that its free end 431 is oriented towards the free endsof the branches 41 and 42. The tab 43, like the branches 41 and 42preferentially comprise elastic deformability, although it can be saidthat they are relatively stiff. The term resilience may be used.

[0031] According to the invention, the branch 42 forms a stop housing 44adapted to receive the free end 431 from the tab 43. This is visible inFIG. 3. In the idle position shown in FIG. 1, the free end 431 of thetab 43 is not necessarily received in the stop housing 44 of the otherbranch 42. The idle position may also be the moulding position or shape.However, as can be seen in FIG. 1, the free end 431 of the tab 43 ispositioned in the vicinity of the stop housing 44 and, in any case, inthe vicinity or in contact with the branch 42. By pressing on thebranches so as to bring them closer together, the free end 431 of thetab moves in relation to the branch 42 in the direction of the stophousing 44. By continuing to press on the branches, the free end 431will be housed in the stop housing 44: however, the stop housing 44shows a configuration capable of keeping the free end 431 locked even ifpressure is continued to be applied onto the branches so as to bringthem closer together. Given that the branches and/or the tab 43 areelastically deformable, it is possible to bring the free ends of thebranches 41 and 42 closer together by means of elastic deformation ofthe branches and/or the tab 43, as shown by the dotted lines in FIG. 3.The tab 43 prevents the branches 41 and 42 from coming closer togetherby pivoting around the bend 40. Indeed, the angle produced by thebranches at the bend 40 remains unchanged when the branches are pressedto bring them closer together. The stiffness of the spring isessentially produced directly by the tab which acts as a lock or propbetween the branches.

[0032] However, it is possible to bring the branches back into contactwith each other so as to extend relatively in parallel by preventing thefree end 431 from being inserted into the stop housing 44 of the branch42. This is shown in FIG. 2. For this, it is simply necessary to forcethe tab 43 slightly so that it passes over the stop housing 44 withoutbeing inserted into it. The free end 431 may then be positioned beyondthe stop housing 44, i.e. between said housing and the bend 40. Thiswould not apply if the tab 43 extends in the other direction, i.e.towards the free ends of the branches. It is clearly seen in FIG. 2 thatthe tab 43 is relatively parallel to the branches 41 and 42 which arealso relatively or perfectly parallel. In order to enable the tab 43 tobe housed between the branches, it must comprise a certain elasticity atits junction with the branch 41 and, in addition, the branch 41 forms awindow 430 inside which the tab 43 may be housed. The spring in FIG. 2is extremely flat, its thickness corresponding approximately to thethickness of the spring at the bend 40. The tab 43, i.e. the variationmeans, is practically inoperative in this position since the free end431 is not inserted in the stop housing 44. However, the tab 43, due tothe fact that it is elastically deformed, tends to exert a force on thebranches by increasing the distance between them. Consequently, the tab43, even in the practically inoperative positive, contributes, inaddition to the bend 40, to the stiffness of the spring which tends toreturn the branches 41 and 42 to the idle position as shown in FIG. 1.However, the stiffness produced by the bend 40 and the practicallyinoperative tab is not considerable such that a minimal force issufficient to keep the spring in the configuration in FIG. 2. Byreleasing the spring when it is in the configuration in FIG. 2, thebranches 41 and 42 will pivot in relation to each other around the bend40 assisted by the release of the tab 43. When the branches areseparated, the free end 431 of the tab 43 will pass over the stophousing 44 and continue its path to the position shown in FIG. 1. Thespring is then in the idle position. By pressing again on the branchesso as to bring them closer together, the free end 431 will be insertedand remain locked in the stop housing 44. The subsequent dynamicbehaviour has already been described above. It is easy to understandthat the stiffness of the spring when the tab 43 is inserted in the stophousing 44 is considerably greater than the stiffness of the spring inthe configuration in FIG. 2, i.e. with the tab 43 disengaged from thestop housing 44. The stiffness of the spring in the configuration inFIG. 2 may just be sufficient to enable the tab 43 to be inserted intothe housing 44. However, it is preferable to provide a margin such thatthe tab 43 is positioned in front of the housing as shown in FIG. 1.With no external intervention to force the tab 43, it will never be ableto return to its position as shown in FIG. 2. Indeed, the stop housing44 acts as an impassable barrier or stop for the free end 431. It isonly by forcing the tab 43 that it is possible to restore theconfiguration in FIG. 2.

[0033] Using the spring stiffness variation means, the spring comprisestwo different stiffness values, i.e. a low value when the branches areseparated from a maximum compressed state (FIG. 2), and a higher valuewhen the branches are brought closer together from the idle position inFIG. 1. This difference in stiffness values is a particularlyadvantageous characteristic in certain applications as seen below.

[0034] Such a spring may for example be produced from a cut and bentmetal blade. The spring may preferentially be produced from mouldedplastic.

[0035] The spring as described above has a special application in afluid product dispenser as shown in FIGS. 4 and 5.

[0036] In this non-restrictive example of an embodiment, the dispensermay be produced from two sheets of flexible complex film 1 and 2 whichare welded together on their edge 11, 12 so as to define a volumebetween them which is approximately equivalent to that of a fluidproduct reservoir 3. An insert 5 may also be placed between the twosheets 1 and 2: this insert 5 defines a dispensing outlet 50 and ahousing wherein a porous fibre 6 may be housed so as to extend insidethe reservoir 3. This fibre 6 is intended to be impregnated with fluidproduct contained inside the reservoir 3. Once this fibre is soaked inproduct, it is simply necessary to pass an air stream through the fibre,which creates a two-phase distribution at the dispensing outlet 50 ofthe insert 5. At the front of the dispensing outlet 50, the two sheets 1and 2 welded together define a tear-off or fold-away strip 12 whichseals the dispensing outlet 50 so as to isolate the reservoir 3 from theoutside.

[0037] According to the invention, the reservoir 3 contains a spring 4which is placed between the two sheets 1 and 2. The spring 4, as shownin FIG. 2, acts at least on one wall of the dispenser, which may be theactuation wall, so as to increase the internal volume of the reservoir3. According to a particularly beneficial characteristic, the spring 4is fully compressed as shown in FIG. 2, while the sealing component 12seals the dispensing outlet 50 and thus isolates the reservoir 3 fromthe outside. In other words, the reservoir 3 was sealed during itsmanufacture with the fully compressed spring such that the reservoir isat minimum volume. In this case shown in FIG. 1, the reservoir 1contains practically only fluid product and practically no gas or noneat all. Given that the reservoir 3 is perfectly isolated from theoutside by the sealing component 12, the spring 4 cannot be slackenedinside the reservoir 3 due to the atmospheric pressure exerted on thewalls 1 and 2 of the reservoir. The dispenser can then be stored beforeuse in this state, it is particularly thin with a thickness definedapproximately by the thickness of the spring 4 in its completelycompressed state added to the cumulative thickness of the two sheets offilm 1 and 2. The spring 4 then defines a minimum volume wherein thefluid product is stored without being subjected to practically anypressure. In this way, there is no risk of leaks due to crushing of thereservoir 3. Such a dispenser may for example be inserted in a magazinesince it is particularly flat and particularly resistant to pressure.

[0038] As soon as the sealing component 12 is removed, air can enterinside the reservoir 3 via the dispensing outlet 50 such that the spring4 can slacken inside the reservoir so as to increase its internalvolume. This is possible by means of the stiffness of the springproduced by the bend and the elastically compressed tab, located,however, outside the stop housing. It is sufficient for this stiffnessto enable the branches to separate in spite of the resistance of thesheets composing the reservoir. The reservoir 3 is then filled withfluid product and gas, generally air. To obtain dispensing of sprayedproduct, it is simply necessary to press on the wall 1 with your thumbfor example against the action of the spring 4 so as to discharge theair via the fibre 6 impregnated with fluid product. The air passingthrough the impregnated fibre 6 creates two-phase spraying at thedispensing outlet 50. As soon as the pressure is released on theactuation wall 1, it returns to its shape shown in FIG. 2, due to theelastic action of the spring 4.

[0039] The spring 4 acts as a spacer in the storage state (FIG. 4) bydetermining a minimum volume for the reservoir 3, as a primer when thesealing component 12 is torn off by increasing the volume of thereservoir 3 and as a return spring when actuated by pressing on theactuation wall 1.

[0040] The use of a spring as defined above with reference to FIGS. 1 to3 is particularly advantageous in this type of dispenser, given that itmay be placed in the reservoir when the dispenser is manufactured, withno specific orientation, due to the fact that the spring is positionedautomatically on one of these two branches. In addition, it is extremelyflat when totally compressed, which makes it possible to produceparticularly flat dispensers, which is advantageous for theabove-mentioned reasons. It is also important to note that, whencompletely compressed, the spring does not press very strongly on thesheets forming the reservoir. Indeed, due to the low value of the springstiffness in this position corresponding to that in FIG. 2, the branchesare not pushed strongly apart, and, for this reason, the branches do notpress as strongly against the sheets. The advantage is that the sheetsare not marked or very slightly marked by the branches due to their lowpressure. On the other hand, as soon as the spring is able to slackendue to the penetration of air into the reservoir, the tab 43 may beinserted in the stop housing 44 and the stiffness is then increasedconsiderably. This gives a dispenser with a very effective returnspring, while in the completely compressed position in FIG. 2, thisspring only showed a considerably weaker force.

[0041] In FIG. 5, it is possible to see, in dotted lines, thedeformation of the spring 4 when the dispenser reservoir is pressed. Itis preferable for the tab and the branch forming the stop housing todeform elastically to increase the clearance of the spring.

[0042] Using this specific spring with variable stiffness, it ispossible to produce a dispenser from simple fluid product packaging withno shape retention.

What is claimed is:
 1. Spring (4) comprising two branches (41, 42)connected by a bend (40) such that the branches form, in the idleposition, an acute angle, said branches being elastically mobile inrelation to each other by relative pivoting around the bend until theycome into contact with each other so as to be extended relatively inparallel, characterised in that it comprises spring stiffness variationmeans (43, 44) which produce different stiffnesses depending on whetherthe spring is compressed or slackened, said variation means producing alow stiffness when the branches are extended relatively in parallel anda greater stiffness when the branches are forced together from the idleposition.
 2. Spring according to claim 1, wherein the spring stiffnessvariation means comprise locking means preventing the branches frombeing returned to a relatively parallel position from the idle position.3. Spring according to claim 1, wherein the branches (41, 42) areelastically deformable.
 4. Spring according to claim 2, wherein thevariation means (43) are elastically deformable.
 5. Spring according toclaim 1, wherein the variation means comprise a tab (43) attached to aso-called first branch (41) and extending between the two branches tothe other so-called second branch (42), said tab (43) comprising onefree end (431) and one end connected to the first branch, said secondbranch (42) comprising a stop housing (44) intended to receive the freeend (431) of the tab, said free end (431) being locked at a stop in thehousing (44) when the two branches are forced against each other, thuspreventing the branches from being brought against each other bypivoting around the bend.
 6. Spring according to claim 5, wherein thetab (43) extends with its free end (431) oriented approximately towardsthe bend (40), the free end of the tab being located between the stophousing (44) and the bend (40) when the branches are relativelyparallel.
 7. Spring according to claim 5, wherein the tab (43) extendswith its free end (431) oriented relatively towards the free ends of thebranches, the free end (431) of the tab (43) being located between thestop housing (44) and the free ends of the tabs when the branches arerelatively parallel.
 8. Spring according to claim 5, wherein the firstbranch (41) forms a window (430) wherein the tab (43) is housed byelastic deformation when the two branches are extended relativelyparallel.
 9. Spring according to claim 5, wherein the tab (43) extendsso that its free end (431) is automatically housed and remains locked inthe stop housing (44) of the second branch (42) when the two branchesare compressed against each other.
 10. Spring according to claim 1,produced by plastic moulding.
 11. Fluid product dispenser comprising: areservoir (3) containing said fluid product and equipped with at leastone actuating wall (10) on which pressure is exerted to reduce thevolume of the reservoir, a dispensing outlet (50) through which thefluid product is dispensed, characterised in that the reservoir (3)contains a spring (4) according to any of the above claims. 12.Dispenser according to claim 11, wherein a removable sealing component(12) seals the dispensing outlet (50) and thus isolates the reservoir(3) from the outside, the spring (4) being compressed so as to occupy aminimum volume when the sealing component seals the dispensing outlet.13. Dispenser according to claim 12, wherein the spring (4) is slackenedto increase the volume of the reservoir as soon as to sealing componentis removed by admitting gas into the reservoir via the dispensingoutlet.